Causes and Diagnoses

Causes and Diagnoses of Myositis

Causes

The exact cause of myositis is not known. However, a wide range of factors can trigger it. Myositis may be triggered by:

• Infections, like the cold or flu.
• Certain medications.
• Having another autoimmune disorder, like lupus, rheumatoid arthritis or scleroderma.

Diagnosis

Getting an accurate diagnosis helps your care team make an effective treatment plan. Because myositis is rare, getting care from a trained expert with experience in treating the disease is key.

Your care team will talk with you to better understand your medical history and symptoms. They will assess your health through a physical exam and tests.

The tests may include:

• Blood tests
• EMG (electromyography)
• MRI (magnetic resonance imaging)
• Muscle biopsy